The present invention relates to a method of producing cartons of cigarettes.
Cartons of cigarettes are produced using precut blanks having a number of lateral and a number of transverse yield lines. The lateral yield lines define on the blanks two large lateral panels separated by a central small lateral panel, and having respective longitudinal tabs, which are superimposed one on top of the other to define a further small lateral panel. The transverse yield lines, on the other hand, define end tabs on the ends of at least some of the aforementioned panels.
According to one known method, the blanks as described above are fed successively to a loading station on the cartoning machine, where the central small lateral panel is positioned closing a folding channel formed in a folding jig and having an inwardly-tapering inlet.
A group of packets of cigarettes constituting the content of the carton is fed to the loading station simultaneously with a respective blank, and is pushed into contact with the central small lateral panel and into the folding channel so as to fold the blank in a U about the group. U-shaped folding of the blank is assisted by prefolding the two large lateral panels about the respective yield lines connecting them to the central small lateral panel, which prefolding operation is normally performed using wedge-shaped prefolding spindles of the same shape as the tapered inlet of the folding channel, and which move together with the group of packets as this is inserted inside the folding channel.
The above known method presents several drawbacks due to the presence of the prefolding spindles, which, in addition to seriously impairing access to a critical area such as the loading station, also have a negative effect on blank folding time, by virtue of the spindle travel involved, which is at least equal to the distance traveled by the packets towards the respective blank.